First of all, just want to say that whether you visit earny.com or earny.co they are both the same and legit. Both domains sync to the same one, same company.
I just gave earny a try and the process was quick. Since earny already scan through your receipts in your email inbox such as yahoo mail and google gmail. It does a price check based on the item exact description sku# to get accurate data and check for price change and notify you og the changes. You then allow earny to submit a request for a refund based on your request.
A lot of people said this work greatly with amazon.com purchase and over the year the refund paid off for their amazon prime account. I personally think this is a really way of getting your refund almost automatically just a few click. I think it is safe, just remember to 2FA all your account, and setup alerts on all your banks credit card account for any activities whether it’s purchase deposit withdrawal .. all. So that you will see what’s going on and tackle the issue right away if something bad were to happen.